I'm skeptical that a 700-year-old mito genome can be used as evidence of prehistoric population movements. Obviously, for that sort of thing we'd need a sequence from before recorded history. Nevertheless, the discovery of mtDNA haplogroup U5a2a in the Eastern Pamirs is still very interesting.
The complete mitochondrial genome of one 700-year-old individual found in Tashkurgan, Xinjiang was target enriched and sequenced in order to shed light on the population history of Tashkurgan and determine the phylogenetic relationship of haplogroup U5a. The ancient sample was assigned to a subclade of haplogroup U5a2a1, which is defined by two rare and stable transversions at 16114A and 13928C. Phylogenetic analysis shows a distribution pattern for U5a2a that is indicative of an origin in the Volga–Ural region and exhibits a clear eastward geographical expansion that correlates with the pastoral culture also entering the Eurasian steppe. The haplogroup U5a2a present in the ancient Tashkurgan individual reveals prehistoric migration in the East Pamir by pastoralists. This study shows that studying an ancient mitochondrial genome is a useful approach for studying the evolutionary process and population history of Eastern Pamir.
Ning et al., Ancient mitochondrial genome reveals trace of prehistoric migration in the east Pamir by pastoralists, Journal of Human Genetics advance online publication 29 October 2015; doi: 10.1038/jhg.2015.128